1. Field of the Invention
The present invention relates to a fastening element including an anchor tube having a receiving chamber for a hardenable mass, and drilling head provided at one end of the anchor tube and having at least one inlet opening that opens toward the receiving chamber of the anchor tube, and at least one through-opening that opens outwardly for passing of the hardenable mass therethrough.
2. Description of the Prior Art
Fastening elements of the type described above are used, e.g., for reinforcement of tunnels and mines. To this end, firstly, a borehole is formed in a tunnel or mine roof, e.g., then the borehole is filled with a hardenable mass and, finally, an anchor element is driven into the borehole filled with the hardenable mass.
International Publication WO 03/044324 discloses a fastening element including an anchor tube that forms the anchor element and has a receiving chamber for a hardenable mass and in which, in the region adjacent to the borehole bottom, a mixing element is provided. The fastening element is driven in the preliminary formed borehole and then the hardenable mass stored in the receiving chamber of the anchor tube is delivered through the mixing element. The components of the hardenable mass are mixed up in the space surrounding the anchor tube before the hardenable mass is brought out.
In order to reduce expenses associated with setting of a fastening element of the type discussed above, U.S. Pat. No. 4,055,051 discloses a so-called self-drilling rock anchor, e.g., for reinforcing tunnels and mines. The fastening element is driven in with a power drill in the wall or roof of a tunnel or mine. After a desired anchoring depth of the fastening element has been reached, the drilling process stops and the hardenable mass is forced out, e.g., with a piston that applies pressure to the mass, from the receiving chamber of the anchor tube through the inlet opening and the through-opening into the space surrounding the anchor tube. After the hardenable mass hardens, the fastening element is reliably anchored in the rock material.
The drawback of the fastening element of the U.S. Pat. No. 4,055,051 consists in that the hardenable mass that exits through the through-opening is intermixed only slightly. For an optimal anchoring of the fastening element, with multi-component masses, the slight intermixing of the components is often not sufficient.
German Patent Publication DE 103 01 968 A1 discloses a fastening element of the type discussed above in which a mixing element, which is displaceable into the drilling head, is provided in the receiving chamber. This fastening element, because of a simple setting process and a high quality of the produced anchorage, proved itself as a self-drilling rock anchor. However, for perfect functioning, the displaceable mixing element should have a corresponding shape of guide surfaces and/or the mixing element itself should have an appropriate shape.
Accordingly, an object of the present invention is fastening element having an anchor tube and a drilling head and which can be simply produced.
Another object of the present invention is to provide a fastening element of the type discussed above and which is capable of being driven in, using different setting processes.